RuO₂ thin layers were deposited on Ti supports by thermal decomposition of RuCl₃ at 400°C. Some of the samples were subjected to laser irradiation between 0.5 and 1.5 J cm^-2. Some others to Kr bombardment with doses between 10¹⁵ and 10¹⁶ cm^-2. Modifications introduced by the surface treatments were monitored by cyclic voltammetry and O₂ evolution in H₂SO₄ solution. The voltammetric charge increased with surface treatment almost to the same extent for irradiation and bombardment. The electrocatalytic activity turned out much higher for Kr bombarded samples. Raw experimental data were scrutinized in an attempt to separate geometric from electronic factors. True electrocatalytic effects are clearly seen to prevail over purely surface area effects.